"But I really am hungry"
Sometimes the pull arrives dressed as hunger, and you can't tell them apart. It's ten to four. You had lunch at one. Perhaps you are hungry. Perhaps that's a perfectly good reason to eat, and this whole book is making a fuss about a snack.
Sometimes you are. Let me be plain about that, because this book is not going to ask you to override hunger. If it's ten to four and you're hungry, eat something and eat it properly. The habit isn't eating between meals. It's eating without hunger, for a reason that isn't hunger.
So it's worth being able to tell. The differences below are my own description, drawn from what people commonly report, and not a clinical test. Hunger builds. It's been coming on for a while before you notice it, and it grows if you ignore it. The pull arrives all at once, usually within a minute of something happening. Hunger is felt in the stomach, as emptiness, and sometimes as a lack of energy or a slight headache. The pull is felt in the mouth and in the mind, as a wanting. Hunger will accept a wide range of food. If you're hungry, an apple or a bowl of soup would do. The pull wants a specific thing, usually something rich, salty or sweet, and an apple would be an insult to it. And hunger goes away when you eat and stays away. The pull can go away with eating and come back in half an hour, because the thing it was about hasn't moved.
There's a test in there, and it's the one I'd use. Would an apple do? If yes, you're probably hungry, and you should eat, and it doesn't have to be an apple. If the answer is a firm no, that it has to be the cheese or the crisps, then what you have is the pull, and the ask applies.
Look at your week of notes. My guess is that the hunger column has a lot of twos and threes in it. If it has a lot of sevens and eights, then the problem may be that your meals aren't feeding you, and chapter 18 is about that. It's common, in my observation, for people who eat a great deal between meals to eat rather little at them, out of a wish to make up for the extras. That produces real hunger at four, which then gets answered with crackers, which spoils dinner, which produces real hunger at nine. Feeding yourself properly at meals removes the hunger from the afternoon and leaves only the pull, which is easier to see once it's on its own.